Melting-pot or crucible.



UNITED, STATES PATENT onrucn.

JOHN C. HENDERSON, OF WASHINGTON,.DISTRICT OF COLUMBIA, ASSIGNORTODRIVER- HARRIS COMPANY, 01? HARRISON, NEW JERSEY, A CORPORATION OF NEWJERSEY.

MELTING-POT on orwcnsnn.

* To all whom. it may concern:

Be it known-that I, Jean C. HENDERSON, a citizen of the United States,residin at Washington, in the District of Colum ia, have inventedcertain new and useful Im-. provements in Melting-Pots or Crucibles, ofwhich the following is a full, clear, andexact description.

My invention relates to melting pots or cruclbles for melting metallicsubstances of high melting point, suchas brass, cop.- per and the like,and has for its object to provide a commercially practicable castmetallic melting pot or crucible for use in the manufacturing arts formelting cop per, brass and the like in quantities such as are now meltedin graphite crucibles. It further has for its object to provide such amelting pot or crucible in which the time and fuel required for meltingsubstances of high melting point is reduced largely below that requlredin present practice. It further has for its object to produce such",melting pots or crucibles which shall not be liable to break when hitor handled and may be repeatedly used for many times. The cost of usingcrucibles such as at i present. used is verygreat, due to the fact thatthey frequently break so that they not only have to be replaced but alsooften lose them contents and, moreover, they transmit the heat sosowlyas to consume what I have found to be an unnecessarily long period oftime and great amount of fuel in each heat.

'I have discovered that the cost and loss can be largely reduced byusing a crucible I suchas below specified.

In practice in making a crucible, involving my invention, I cast thesame froman alloy containing fromffive (5) to thirty (30) percent. ofchromium and. fifty (5 0) to ninety (90) per cent..of nickel. Thecombined chromium and nickel preferably amount to sixty() per cent. Thepreferred alloy contains chromium twelve (12)' per cent, nickel sixty(60) per cent, iron twenty-six (26) per cent, and manganese one andone-half (1%) per cent. Cobalt can be substituted for nickel, beinofsubstantially the same'character. Co alt isassociated with iron inMendeleefs table and of substantially the same atomic weight.

Good results can be obtained if the iron con- Y tent above referred tois omitted.

Specification of Letters Patent.

ble embodying my invention, reference being had to the accompanyindrawing which shows a vertical section 0 a crucible embodying myinvention for use in an. ordinary furnace.

; Referring more particularly to the draw- Patented Oct. 2, 1917.-Application filed July 8, 1916. Serial No. 108,102.

i i The following is a description of a cruciings, 1 is .the wall of acrucible of ordinary external shape cast of the alloy above referred to,which is very refractory, and of a conductivity which is low thoughhigher than the conductivity ofgraphite. It has a flat bottom 2 and isadapted to stand upon the floor of a furnace.- The wall thickens'somewhatas'it approaches the base, since the pressure, and heat aremore severe at that point.

The walls of the crucibles embodying my invention are thin, being aboutone-half as thick as the walls of a commercial graphite crucible of thesame dimensions. They are I thin enough to be kept from melting underordinary brass or copper melting conditions,

by the cooling effect of. melting brass orcopper contained therein,until'the brass or [copper reaches the required pouring temperature. Iftoo thick the wall, on account vof'the poor heat conductivity "of itsalloy, is

liable to soften and become porous. In a crucible ten inches in.diameter at the top I have found that making the average thickness ofthe wall about five-eighths of an inch My crucibles, on acgives goodresults. count of their thinness and specific conduct1vity,'conduct theheat of a furnace to their contents much more readily than do graphitecruciblesso that the time and fuel .for each meltis reduced. They resistthe action of molten brass or copper so that the quality of suchcontents is not afl'ected'by the crucible; They remainstrong at the hightemperature necessary to'melt brass or copper and can be used repeatedlymany times. They do not have, to be heated or dried before using as isthe case with graphite crucibles audit is unnecessary to keep a largereserve stock on hand. They are highly resistant to oxidation and thougha slight film forms, constituting a coating.

3 upon the surface, that filmprotec'ts the body ofthe crucible and isitself refractory non-flaking and-very resistant to the action of itscontents. i

In operating .with a crucible embodying 110 my invention, it is put intoa furnace in the ordinary manner.

pot

in Mendeleefs table and of Gare should be taken not to overheat it, i.6., to not expose it to a melting temperature above 2000 F. for aconsiderable period after the melting of the contents is completed,since if that .is done it may be injured. It will, however, Withstandany heat treatment necessary for melting brass, copper and the like.

As will be evident to those slm'lled in the art, my invention permits ofvarious modifications Without departing from the spirit or the scope ofthe appended claims.

What ll claim is:

1. A cast thin Walled metallic melting composed of a highly refractoryalloy of low heat Conductivity and resistant to the action of moltenbrass, said pot having a refractory, non-flaking coating upon itsexposed surface. I

2, A. cast metallic melting pot composed of a highly refractory alloycontaining chromium and a metal associated With iron the same atomicWeight as iron,

substantially rattan 3. A cast metallic melting pot composed of a highlyrefractory alloy containing chromium and a metal associated with iron inMendeleefs table and of substantially the same atomic Weight as iron,said pot having a refractory, non-flaking coating upon its exposedsurface.

4. Acast thin Walled metallic melting pot composed of a highlyrefractory alloy containing chromium and a metal associated with iron inMendeleefs table and of substantially the same atomic Weight as iron,said pot having a refractory, non-flaking coating upon its exposedsurface, and the Wall thereof increasing in thickness as it approachesthe base.

5.: A cast metallic melting pot, composed of a highly refractory alloycontaining nickel and a metal having the characteristics of chromium,the combined nickel and said other metal amounting to at least sixty percent. (60%) of the alloy.

JOHN 0. HENDERSQN.

